Lubricating oils



Patented May 2, 1939 UNITED STATES LUBRICATING OILS Bert H. Lincoln'and Gordon D. Byrkit, Ponca City, Okla., assignors, by mesne assignments, to

The

Lubri-Zol Development Cleveland, Ohio, a corporation of Corporation, Delaware No Drawing. Application February 15, 1936,

Serial No. 64,167

18 Claims.

Our invention relates to lubricating oils and more particularly to mineral oils possessing improved characteristics particularly in having lower pour points and greater load carrying ability of film strength than straight mineral oils.

This application is a continuation in part of our co-pending application Serial No. 30,733, filed July 10, 1935 which discloses but does not claim certain of the matter disclosed and claimed in this application.

One of the prime requirements for an automotive lubricating oil is that it be sufficiently fluid at all temperatures encountered in the operation of the equipment to be lubricated that it may flow through pumps and feed lines to the bearings and other devices to be lubricated. No lubricant, however excellent, can lubricate unless it is properly applied to the part to be lubricated. The presence of wax in hydrocarbon lubricants prevents proper application in most instances and under many operating conditions such as are encountered in cold weather. It has been found that the removal of parafiin wax by various means such as filter pressing at a low temperature with or without a solvent, aids in producing a lubricating oil of lower pour point which can be properly applied to the mechanisms requiring lubrication. Wax and petrolatum, which also serve to raise the pour point, may be removed by centrifugal processes.

It is usually necessary, in order to produce oils having pour points of approximately F. toaccomplish this removal of wax in two stages when neutral oils are being so treated. The first stage or hot pressing consists in filter pressing the partly solidified oil cooled only to a relatively high temperature, say 45 to 50 F. when considerable wax is removed without the use of large amounts of refrigeration, and without the necessity. ofhandling a very solid mass of oil and wax such as'would be obtained by chilling directly to a.lower temperature. The oil forming the filtrate from this hot pressing from which considerable wax has been removedjis then further chilled 'to approximately F; below the pour point desired for the finished oil and filtered again. This operation is known as cold pressing. These operations, designed to remove parafiin wax from light oils, are costly since they require expensive equipment, including filter presses suitable for operation under high pressures, pumps capable of moving the semi-solid oil-wax mixture, refrigerating systems for cooling large quantities of the Wax-bearing oil to extremely low temperatures, etc.

The high cold test of bright stocks and such heavy oils is likewise due to their content of waxy material which is, however, of a different sort known as petrolatum. Filter pressing of the chilled oil in this case is not suitable for remov- 5 ing petrolatum because in the pressing operation the petrolatum. behaves as a jelly-like material, packing tightly into the pores of the filter medium and stopping the flow of oil through the cake. Furthermore, this jelly-like mass is much more difficult to pump to the presses than the slurry of wax crystals and oil formed in the case of the lighter oils. Because .of these diificulties, it is preferred to dissolve the heavy stock in diluent, chill, and centrifuge the precipitated petrolatum from the lighter naphtha solution of oil. After the centrifugal separation, it is necessary to remove the diluent and recover it in order to make the process economical. Here again, it is obvious that expensive equipment, including blending tanks for dissolving the heavy oil in naphtha, refrigerating equipment for cooling both the oil and an equal weight or more of naphtha to excessively low temperatures, pumps which can move the chilled solution and petrolatum to the centrifuges, and most expensive of all the high speed centrifuge machines of which a large number are required.

It is apparent that the cost of manufacturing a lubricating oil, using these methods of removing wax and petrolatum in order to obtain products having low cold tests, is much greater than those manufactured by our method, which contemplates the use of a pour point depresser by which all these expensive processes and equipmerit are rendered unnecessary. Furthermore,

it is possible to obtain lubricants by our process which have equally low pour points, but which contain part or all of the wax and/or petrolatum. From the point of view of improving the viscosity 40 index of the oil, it is a distinct advantage to have these waxy materials left in the oil. (See Dean and Davis, Chemical and Metallurgical Engineer'- ing, vol. 36, 1929, page 618), I

These materials, which tend to raise the pour point of a lubricating oil, apparently act by partly crystallizing from the remainder of the oil in such a way that a lattice or honeycomb structure is formed which prevents the free flow of the oil. Another method of lowering the pour point 59 of oils depends not on removing these materials responsible for such a lattice structure, but on adding to the oil containing all or only part of them, such a material as will completely or partially inhibit or interfere with the formation of lowering of cold test obtained by the cold pressthe same stock would be limited to this theory of how the materials covered in this invention act to lower the pour point, we believe they act somewhat in this manner.

.We contemplate the useof our addition agents particularly in lowering the cold test and improving the film strength 01' partially dewaxed oils, though the additive materials here described are suited for use with any hydrocarbon oil, whether wholly dewaxed or whether containing all of its natural wax content. It is relatively inexpensive to dewax oils partially by the hot pressing process described above, because the temperatures are comparatively easily attained and maintained during the pressing operation.' A great lowering of the cold test of the oil is obtained in this way at little expense in contrast to the relatively small ing process which is, at the same time, considerably more expensive because it is necessary to attain and maintain a much lower temperature in the oil by means of greatly increased refrigeration requirements. It is obvious that greater quantities of our addition agents will be required to lower the pour point of a wholly undewaxed oil than that of one which has been hot pressed. Thus in the preferred embodiment of our invention, we hot press the oil so as to remove large quantities of wax and lower the pour point in this manner, since it is cheaper than the use of ad dition agents; but rather than use the relatively expensive cold pressing process for removing the remainder of the wax and simultaneously suffer.- ing the volumetric loss of lubricant involved, we add one-of the addition agents here described'so as to obtain the same lowering of the pour point by this less expensive method and without loss of any of the lubricant.

In dewaxing oils at the centrifuge to lower cold test it is found that a large part of the wax may be removed with ease at low cost. However, removal of additional amounts of wax becomes increasingly more diilicult and more expensive. For example, a 20 F; to 30 F. pour point oil may be easily and cheaply produced from a stock having a 90 F. pour point. However, the difficulty and expense of producing a F.pour point oil from be excessive and may be double the cost of producing the F. to F. pour point oil.

With regard to the desirability of producing lubricating oils of improved film strengths, .it is well known that most lubricating oils are no better, and many of them are poorer, with respect to this characteristic than they were ten years and more ago.. During this same period, engine speeds, compression ratios and horse power of automotive engines have increased considerably. .All these advances in automotive engineering have increased bearing pressures and the demand made on lubricants.

parent. It has been found that certain classes of organic compounds, when blended in small concentrations with mineral oils, serve to improve the 'load carrying ability of the mineral oils so that they are much better adapted to modern lubrication demands than the unblended" oils. The film strengths of both straight mineral and blended lubricating oils may be suitably our blends.

The necessity of a lubricant which has the ability to carry this loadwithout permitting metal-to-metal contact is apmeasured by means of film strength testing machines, a

One of the important features of our invention is that we have discovered a class oi materials which when blended in small percentages, suitably 0.1 to10 percent, with mineral produce both of these effects simultaneously. The advantage'of lowering the pour point and raising the film strength by means of a single addition agent is at once apparent in decreasing the cost of manufacture because these materials are as readily prepared as addition agents designed for either purpose alone. They make necessary only one blending operation, which will tend to reduce manufacturing costs.

The class of materials which we contemplate using to accomplish this dual purpose may be described as halogenated esters formed from acids containing more than ten carbon atoms and poly hydroxyl cyclic organic compounds containing one or more hydroxyl groupsfor each cylic group. These compounds may be prepared in any of the ways known to the art, for example, by the interaction of a higher fatty acid with a polyhydric phenol followed by halogenation. Another method. which may be used consists of esterifying the previously halogenated phenol with a higher fatty acid. Also, the acid may first be halogenated and then converted into the ester by reaction with the polyhydric phenol or other cyclic compound. The reaction products are carefully refined to remove free hydrochloric acidby any of the well known means, such as washing with dilute caustic or carbonate solution. Washing with sodium sulfite solution serves to remove unstable halogen from the material which is then washed and suitably dried.

These esters may be derived from saturated or unsaturated fatty acids having straight or branched chains which may be further substituted. The polyhydroxyl cyclics may be aromatic or cycloparaflinic in character. While oils serve tochlorine is the cheapest and most readily available halogen, we contemplate using, as well, the other halogens, such as'bromine, and'iodine, since they are also suited to our purpose.

The hydrocarbon portions of these blended oils may be refined lubricating oils or unrefined stocks from paramnic, naphthenic, asphaltic or mixed base crudes. Oils of any viscosity may be treated within the scope of our invention. Special oils such as hydrogenated oils, electrically treated oils, etc., may constitute the hydrocarbon portion of Thus we contemplate treating any petroleum oil to lower its pour point and raise its film strength. 3 I

The following examples will serve to make clear how we practice our invention, but we do not wish to be limited to them:

Example 1 Ninety-nine parts by weight of a well refined Mid-Continent lubricating oil of SAE grade No. 30, having a pour point of 2 F. and a film I strength of 6000 pounds per square inch, and one part by weight of dichlorohydroquinone distea- 1 rate were blended together at 140 F. by mechanical agitation. The blended oil had a pour point of -16 F. and a film strength of 15,300 pounds per square inch. 4

Example- 2 I An addition agent prepared from one molecular proportion of pyrogallol and three molecular pro portions of dichlorostearic acid .was mixed the addition agent.

Example 3 One part by weight of trichlorophenyl stearate blended with ninety-nine parts of SAE 20 parafiin base mineral oil reduced the pour point of the latter from 15 F. to 3 F. and raised the film strength from 5600 to 11,800 pounds per square inch.

Example 4 The chlorinated and refined ester obtained from the action of lauric acid on 4, 4, 4"-trihydroxy triphenyl-methane in the presence of phosphorus oxychloride was blended with a mineral oil having a film strength of 6500 pounds per square inch and a pour point of 2 F., 995 parts by weight of the oil was used with five parts of The blended material had a film strength of 22,800 pounds per square inch and a pour point of 10 F.

It will be understood that certain features and sub-combinations are of utility and may be employed without reference to other features and sub-combinations. This is contemplated by and is within the scope of our claims. It is further obvious that various changes may be made in details within the scope of our claims without departing from the spirit of our invention. It is, therefore, to be understood that our invention is not to be limited to the specific details shown and described.

The term "pour point and the term cold test used herein refer to the commonly accepted definitions used in the petroleum industry and to A. S. T. M. designation D 97-34.

Having thus described our invention, what we claim is:

1. A lubricating oil comprising in combination a major portion of hydrocarbon oil and a minor portion of a halogenated poly hydroxy cyclic ester.

2. A lubricating oil comprising in combination a major portion of hydrocarbon oil and a minor portion of a chlorinated poly hydroxy cyclic ester.

3. A lubricating oil comprising in combination a major amount of hydrocarbon oil and a minor amount of a halogen-bearing ester of an organic acid having more than ten carbon atoms per molecule and a cyclic polyhydroxy compound.

4. A lubricating oil comprising in combination a major amount of hydrocarbon oil and from about 0.10% to 10% by weight of a halogen-bearing ester of an organic acid having more than ten carbon atoms per molecule and a cyclic polyhydroxy compound.

5. A lubricating oil comprising in combination a major amount of hydrocarbon oil and a minor amount of a chlorine-bearing ester of an organi acid having more than ten carbon atoms per molecule and a cyclic polyhydroxy compound.

6. A lubricating 011 comprising in combination a major amount of a hydrocarbon oil and from one-tenth of one percent to ten percent by weight of a chlorine-bearing ester of an organic acid having more than ten carbon atoms per molecule and a. cyclic polyhydroxy compound.

7. A lubricating composition of increased film strength and lowered cold test comprising in combination a major portion of hydrocarbon oil and a minor portion of a halogenated ester formed. from organic acids containing more than ten carbon atoms and poly hydroxy cyclic organic compounds containing at least one hydroxy group for each cyclic group.

8. A lubricating composition of increased film strength and lowered cold test comprising in combination a major portion of hydrocarbon oil and from .1 percent to 10 percent by weight of a halogenated ester formed from organic acids containing more than ten carbon atoms and poly hydroxy cyclic organic compounds containing at least one hydroxy group for each cyclic group.

9. A lubricating composition of increased film strength and lowered cold test comprising in com-.

bination a major portion of hydrocarbon oil and a minor portion of a chlorinated ester formed from organic acids containing more than ten carbon atoms and poly-hydroxy cyclic organic compounds containing at least one hydroxy group for each cyclic group.

10. A lubricating composition of increased film strength and lowered cold test comprising in combination a major portion of hydrocarbon oil and from .1 percent to 10 percent by weight of a chlorinated ester formed from organic acids containing morev than ten carbon atoms and poly hydroxy cyclic organic compounds containing at least one hydroxy group for each cyclic group.

1. A lubricating oil comprising in combination a major amount of a hydrocarbon oil and from about 0.10% to 10% by weight of a halogenbearing ester of an organic acid having more than ten carbon atoms per molecule and an arc matic polyhydroxy compound.

12. A lubricating oil comprising in combination a major amount of hydrocarbon oil and from about 0.10% to 10% by weight of a chlorine-bearing ester of an organic acid having more than ten carbon atoms per molecule and an aromatic polyhydroxy compound.

13. 'A lubricating oil comprising in combination a major amount of hydrocarbon oil and from about 0.10% to 10% by'weight of a. chlorine-bearing ester of an organic acid having more than ten carbon atoms per molecule and a polyhydroxy phenol.

14. A lubricating oil comprising in combination a major amount of hydrocarbon oil and a minor amount of the ester prepared from one molecular proportion of pyrogallol and three molecular proportions of dichlor stearic acid.

15. A lubricating oil comprising in combination a major amount of hydrocarbon oil and a minor amount of the composition obtained by halogenating the ester formed from lauric acid and a cyclic polyhydroxy compound.

16. A lubricating oil comprising in combination a major amount of hydrocarbon oil and a minor amount of the composition obtained by halogenating the ester formed from. lauric acid and 4, 4', 4" trihydroxy triphenyl methane.

17. A lubricating oil comprising in combination a major amount of hydrocarbon oil and a minor amount of the composition obtained by halogenating the ester formed from stearic and a cyclic polyhydroxy compound. I

18. A composition of matter comprising in combination a major portion of hydrocarbon oil and a minor portion of dichlorohydroquinone distearate.

BERT H. LINCOLN. GORDON D. BYRKIT. 

